The Veterans Administration Cooperative Urological Research Group is currently following patients in 4 clinical trials of treatment for patients with genitourinary cancer. These are all cooperative studies involving altogether some 26 Veterans Administration Hospitals. (1) Main Prostate I, which compares the effect of two treatments (prostatectomy alone, and prostatectomy with estrogen) for Stages I-II, and of 4 treatments (estrogen, orchiectomy, estrogen plus orchiectomy, and placebo control) for Stages III-IV. (2) Main Prostate II, which also compares the effect of 2 treatments (prostatectomy alone and placebo control) for Stages I-II and of 4 treatments (3 levels of estrogen and placebo control) for Stages III-IV. (3) Main Prostate III, which compares placebo versus prostatectomy for operable Stage I-II patients. Inoperable Stage I-II patients are randomly assigned to placebo or 1.0 mg diethylstilbestrol. All eligible State III-IV patients are randomized to 1 of 4 treatments: 1.0 mg diethylstilbestrol, 30 mg provera, 2.5 mg premarin, or 30 mg provera plus 1.0 mg estrogen. (4) Urinary Bladder II, which compares transurethral surgery followed by oral placebo, oral pyridoxine, or topical instillation of thio-TEPA in treating Stage I tumors of the bladder. Acquisition of patients for two new major clinical trials is planned for April 1975. In Main Prostate IV placebo, 1.0 mg diethylstilbestrol (DES), and 1.0 mg DES plus aspirin will be compared in previously untreated patients with low stage and tumor grade. In untreated patients with more advanced disease, 1.0 mg DES will be compared to Flutamide (a new non-steroidal anti-androgen) and to a combination of the two. In the second mew protocol, designated the Chemotherapy Study, stilphosterol (an estrogen), Estracyt (an estrogen-alkylating agent combination), and L-phenylalanine mustard (an oral alkylating agent) will be compared. In projects (1)-(3) above detailed analyses of histopathology, biochemical measurements and radiographic findings as related to patients prognosis are in progress.